An ajax-based digital music stand for greenstone

This extended abstract describes a digital music stand integrated with the Greenstone digital library software. It features text annotation and an animated fast-to-slow page wipe. Figure 1 illustrates both these features, although it is best appreciated in a live demonstration. Digital annotation provides a non-destructive alternative to a musician's habit of penciling in notes. In Figure 1, slightly over half way down the page, there is a note to watch the fingering. A user can have as many of these as they like, positioned anywhere on the page.

The animated page wipe alleviates (somewhat) the issue of when to turn to the next page. Unlike its physical counterpart, where turning to the next page means you can no longer see the current page, with a digital music stand the next page can gradually be overlaid. The page transition occurring in Figure 1 can be seen as a marked horizontal bar not quite half-way down the page. The speed of the wipe is initially fast, but when it reaches the point where the scroll-bar marker is on the right-hand side of the page, it slows down significantly. This is to give the musician time to finishing playing the last line of the current page. In the event they have already finished playing that line, they will have naturally moved on to playing the top of the next page (which is already displayed).

Rather than adopt a traditional client-side "helper" application for the digital music stand, we have integrated it within Greenstone using AJAX. For instance: next and previous pages are asynchronously loaded in the background; when generating a page, the dimensions of the user's screen is sent to the DL server so it can produce a version that maximizes the available space; and interactions such as adding an annotation, or altering the position of the animation-break are immediately stored as metadata associated with that document. Initially the animated page breaks are set to be between the last two staff systems. This is accomplished as part of the DL ingest process, leveraging off the staff detection step of Optical Music Recognition software.